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Canopy Interception
Canopy interception is the rainfall that is intercepted by the canopy of a tree and successively evaporates from the leaves. Precipitation that is not intercepted will fall as throughfall or stemflow on the forest floor. Many methods exist to measure canopy interception. The most often used method is by measuring rainfall above the canopy and subtract throughfall and stem flow (e.g., Helvey and Patric 965. However, the problem with this method is that the canopy is not homogeneous, which causes difficulty in obtaining representative throughfall data. Another method that tried to avoid this problem is applied by e.g., Shuttleworth et al. 984 Calder et al. 986 and Calder 990 They covered the forest floor with plastic sheets and collected the throughfall. The disadvantage of this method is that it is not suitable for long periods, because in the end the trees will dry due to water shortage, and the method is also not applicable for snow events. The method by Hancock and Crowther 9 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stormwater Management With Trees
Stormwater, also spelled storm water, is water that originates from precipitation (storm), including heavy rain and meltwater from hail and snow. Stormwater can soak into the soil ( infiltrate) and become groundwater, be stored on depressed land surface in ponds and puddles, evaporate back into the atmosphere, or contribute to surface runoff. Most runoff is conveyed directly as surface water to nearby streams, rivers or other large water bodies (wetlands, lakes and oceans) without treatment. In natural landscapes, such as forests, soil absorbs much of the stormwater. Plants also reduce stormwater by improving infiltration, intercepting precipitation as it falls, and by taking up water through their roots. In developed environments, such as cities, unmanaged stormwater can create two major issues: one related to the volume and timing of runoff (flooding) and the other related to potential contaminants the water is carrying (water pollution). In addition to the pollutants carried ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rainfall
Rain is water droplets that have condensed from atmospheric water vapor and then fall under gravity. Rain is a major component of the water cycle and is responsible for depositing most of the fresh water on the Earth. It provides water for hydroelectric power plants, crop irrigation, and suitable conditions for many types of ecosystems. The major cause of rain production is moisture moving along three-dimensional zones of temperature and moisture contrasts known as weather fronts. If enough moisture and upward motion is present, precipitation falls from convective clouds (those with strong upward vertical motion) such as cumulonimbus (thunder clouds) which can organize into narrow rainbands. In mountainous areas, heavy precipitation is possible where upslope flow is maximized within windward sides of the terrain at elevation which forces moist air to condense and fall out as rainfall along the sides of mountains. On the leeward side of mountains, desert climates can exi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canopy (biology)
In biology, the canopy is the aboveground portion of a plant cropping or crop, formed by the collection of individual plant crowns. In forest ecology, canopy also refers to the upper layer or habitat zone, formed by mature tree crowns and including other biological organisms ( epiphytes, lianas, arboreal animals, etc.). The communities that inhabit the canopy layer are thought to be involved in maintaining forest diversity, resilience, and functioning. Sometimes the term canopy is used to refer to the extent of the outer layer of leaves of an individual tree or group of trees. Shade trees normally have a dense canopy that blocks light from lower growing plants. Observation Early observations of canopies were made from the ground using binoculars or by examining fallen material. Researchers would sometimes erroneously rely on extrapolation by using more reachable samples taken from the understory. In some cases, they would use unconventional methods such as chairs susp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Precipitation (meteorology)
In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls under gravitational pull from clouds. The main forms of precipitation include drizzle, rain, sleet, snow, ice pellets, graupel and hail. Precipitation occurs when a portion of the atmosphere becomes saturated with water vapor (reaching 100% relative humidity), so that the water condenses and "precipitates" or falls. Thus, fog and mist are not precipitation but colloids, because the water vapor does not condense sufficiently to precipitate. Two processes, possibly acting together, can lead to air becoming saturated: cooling the air or adding water vapor to the air. Precipitation forms as smaller droplets coalesce via collision with other rain drops or ice crystals within a cloud. Short, intense periods of rain in scattered locations are called showers. Moisture that is lifted or otherwise forced to rise over a layer of sub-freezing air at the surface may be condense ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Throughfall
In Hydrology, throughfall is the process which describes how wet leaves shed excess water onto the ground surface. These drops have greater erosive power because they are heavier than rain drops. Furthermore, where there is a high canopy, falling drops may reach terminal velocity, about , thus maximizing the drop's erosive potential. Rates of throughfall are higher in areas of forest where the leaves are broad-leaved. This is because the flat leaves allow water to collect. Drip-tips also facilitate throughfall. Rates of throughfall are lower in coniferous forests as conifers can only hold individual droplets of water on their needles. Throughfall is a crucial process when designing pesticides for foliar application since it will condition their washing and the fate of potential pollutants in the environment. See also *Stemflow *Canopy interception Canopy interception is the rainfall that is intercepted by the canopy of a tree and successively evaporates from the leaves. Pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stemflow
In hydrology, stemflow is the flow of intercepted water down the trunk or stem of a plant. Stemflow, along with throughfall, is responsible for the transferral of precipitation and nutrients from the canopy to the soil. In tropical rainforests, where this kind of flow can be substantial, erosion gullies can form at the base of the trunk. However, in more temperate climates stemflow levels are low and have little erosional power. Measurement There are a variety of ways stemflow volume is measured in the field. The most common direct measurement currently used is the bonding of bisected PVC or other plastic tubing around the circumference of the tree trunk, connected and funneled into a graduated cylinder for manual or a tipping bucket rain gauge for automatic collection. At times the tubing is wrapped multiple times around the trunk is order to ensure more complete collection. Determining factors Precipitation The primary meteorological characteristics of a rainfall event tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hardwood
Hardwood is wood from dicot trees. These are usually found in broad-leaved temperate and tropical forests. In temperate and boreal latitudes they are mostly deciduous, but in tropics and subtropics mostly evergreen. Hardwood (which comes from angiosperm trees) contrasts with softwood (which is from gymnosperm trees). Characteristics Hardwoods are produced by angiosperm trees that reproduce by flowers, and have broad leaves. Many species are deciduous. Those of temperate regions lose their leaves every autumn as temperatures fall and are dormant in the winter, but those of tropical regions may shed their leaves in response to seasonal or sporadic periods of drought. Hardwood from deciduous species, such as oak, normally shows annual growth rings, but these may be absent in some tropical hardwoods. Hardwoods have a more complex structure than softwoods and are often much slower growing as a result. The dominant feature separating "hardwoods" from softwoods is the presence o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amazonian Forest
The Amazon rainforest, Amazon jungle or ; es, Selva amazónica, , or usually ; french: Forêt amazonienne; nl, Amazoneregenwoud. In English, the names are sometimes capitalized further, as Amazon Rainforest, Amazon Forest, or Amazon Jungle. or Amazonia is a moist broadleaf tropical rainforest in the Amazon biome that covers most of the Amazon basin of South America. This basin encompasses , of which are covered by the rainforest. This region includes territory belonging to nine nations and 3,344 formally acknowledged indigenous territories. The majority of the forest is contained within Brazil, with 60% of the rainforest, followed by Peru with 13%, Colombia with 10%, and with minor amounts in Bolivia, Ecuador, French Guiana, Guyana, Suriname, and Venezuela. Four nations have " Amazonas" as the name of one of their first-level administrative regions, and France uses the name "Guiana Amazonian Park" for its rainforest protected area. The Amazon represents over half ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Water Scarcity
Water scarcity (closely related to water stress or water crisis) is the lack of fresh water Water resources, resources to meet the standard water demand. There are two types of water scarcity: physical or economic water scarcity. Physical water scarcity is where there is not enough water to meet all demands, including that needed for ecosystems to function effectively. Desert climate, Arid areas for example Central and West Asia, and North Africa often suffer from physical water scarcity. On the other hand, economic water scarcity is caused by a lack of investment in infrastructure or technology to draw water from rivers, aquifers, or other water sources, or insufficient human capacity to satisfy the demand for water. Much of Sub-Saharan Africa has economic water scarcity. The essence of global water scarcity is the geographic and temporal mismatch between fresh water demand and availability. At the global level and on an annual basis, enough freshwater is available to meet such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Journal Of Hydrology
''Journal of Hydrology'' () is a peer-reviewed academic journal published by Elsevier about hydrological sciences including water based management Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a s ... and related policy issues. External links * Hydrology journals Elsevier academic journals {{Hydrology-journal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interception (water)
Interception refers to precipitation that does not reach the soil, but is instead intercepted by the leaves, branches of plants and the forest floor. It occurs in the canopy (i.e. canopy interception), and in the forest floor or litter layer (i.e. forest floor interception ). Because of evaporation, interception of liquid water generally leads to loss of that precipitation for the drainage basin, except for cases such as fog interception, but increase flood protection dramatically, Alila et al., (2009). Intercepted snowfall does not result in any notable amount of evaporation, and most of the snow falls off the tree by wind or melts. However, intercepted snow can more easily drift with the wind, out of the watershed. Conifers have a greater interception capacity than hardwoods. Their needles gives them more surface area for droplets to adhere to, and they have foliage in spring and fall, therefore interception also depends on the type of vegetation in a wooded area. Mitscherlich ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Forest Floor Interception
Forest floor interceptionGerrits, A.M.J. and Savenije, H.H.G. 2011. (invited) Forest floor interception. In Levia, D.F., Carlyle-Moses, D.E. and Tanaka, T. (Eds.), Forest Hydrology and Biogeochemistry: Synthesis of Past Research and Future Directions. Ecological Studies Series, No. 216, Springer-Verlag, Heidelberg, Germany is the part of the (net) precipitation or throughfall that is temporarily stored in the top layer of the forest floor and successively evaporated within a few hours or days during and after the rainfall event. The forest floor can consist of bare soil, short vegetation (like grasses, mosses, creeping vegetation, etc.) or litter (i.e. leaves, twigs, or small branches). See also * Interception (water) * Canopy interception Canopy interception is the rainfall that is intercepted by the canopy of a tree and successively evaporates from the leaves. Precipitation that is not intercepted will fall as throughfall or stemflow on the forest floor. Many methods exist to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
